Total palliative care from the early phase of cancer treatment is recommended to relieve both physical and psychological distress. To accomplish total palliative care, psycho-oncology plays an important role in psychological care. Psycho-oncology investigates the relationship between cancer and psychological issues, and has two aspects. The first and main aspect is to investigate the influence of cancer on the psychological status of patients with cancer. The other aspect is to investigate the influence of psychological issues on survival of patients with cancer or its prevention. In fact, psychological symptoms are frequent in patients with cancer, and depression is one of the most important because it could cause suicides. However, previous studies have shown that depression is often missed and untreated. Therefore, depression should be detected and treated early.